Abstract
BACKGROUND: Noninvasive mechanical ventilation is being used increasingly to obviate the necessity for endotracheal intubation and mechanical ventilation in patients in respiratory distress from acute exacerbations of chronic obstructive pulmonary disease (COPD). METHODS: The short-term (45-minute) therapeutic efficacy of nasal intermittent positive-pressure ventilation (NIPPV) and external high-frequency oscillatory ventilation was assessed in 20 COPD patients with an acute decompensation episode. Supplemental oxygen was discontinued and the two ventilatory methods were alternated. During the 24-48 hours after admission, the patient completed a 3-hour study session divided into four 45-minute periods, ie, baseline, first ventilatory mode, pause, and second ventilatory mode. NIPPV was delivered by a standard pressure ventilator in the assist mode, with a commercial nasal mask (Sullivan). The Hayek oscillator was used for high-frequency oscillatory ventilation. RESULTS: After 45 minutes of NIPPV, we observed statistically significant decreases in the respiratory rate and PaCO2 and significant increases in SaO2 and pH. After 45 minutes of high-frequency oscillatory ventilation, we observed statistically significant decreases in PaCO2 and SaO2 with significant increases in the respiratory rate and pH. Differences between decreases in PaCO2 attained with both modes of ventilation were less than 5 torr in 13 patients, between 5 and 10 torr in 6 patients, and higher than 10 torr in 1 patient. CONCLUSIONS: Use of either method of ventilatory support resulted in improvement in alveolar ventilation, with significant changes in PaCO2 and pH. Given that cooperation from the patient to decrease respiratory-muscle activity is required for successful NIPPV, the degree of the patient's cooperation is an important aspect to be considered in the selection of one of the two techniques.
Get full access to this article
View all access options for this article.